[vhcook]

Normally, with Mecanum, the driver has one joystick axis for forward, one for strafe, and one for twist, which may or may not be spread across two joysticks (depending on whether you have joysticks with a twist axis) using the holonomic drive VI.

Normally for tank drive, the driver has one axis to control forward/back motion of each pair of wheels (left/right). This would eliminate the strafing movement that is usually the point of having Mecanum, but can be done using the stock tank drive VI if that's what you want.

Can you please elaborate on what you would expect to happen for various joystick movements? I don't quite understand what result you are trying to achieve.